It started after getting a totem. She wouldn't leave the alter room, and just kept kneeling instead, even though she would indicate 'let's go' (or some such). After just dismissing her and coming back to Whiterun later, she seemed to be working again. But whenever I go somewhere, she'll just randomly stand still and not follow, even after leaving the area through a loading screen. Sometimes when I come back to find her, she'll come abruptly running. Other times she'll just continue to stand there.
I thought 1.3 would have fixed it, but now it seems worse. :sadvaultboy: